d = {
    'Alice': 45,
    'Bob': 60,
    'Candy': 75,
    'David': 86,
    'Ellena': 49
}

#
if(d.get('Alice') != 'none'):
    d['AliceOld'] = d.get('Alice')
    d['Alice'] = 70

if('Nancy' not in d):
    print('no man named Nancy')
    d['Nancy'] = 0

print(d)